In standard integrated circuit chips, it is necessary to conduct alternating current (AC) and burn-in tests. These tests are normally conducted by packaging the chip into a physical package with external leads connected to the chip pads, and connecting the external leads to a test socket, which is then placed onto a board. The entire board, containing a plurality of chips and test sockets, may then be AC tested and tested at higher than normal operating temperatures and voltages (burn-in) to overstress the chips.
Flip-chip technology is a multi-chip technology in which the base chips are flip mounted on a thermally matched circuit board rather than using individual chip packages. A substrate such as a circuit board having solder bumps corresponding to the chip bumps is matched to the chip by "flipping" the chip over and onto the substrate. The chip and the substrate are then heated to reflow the solder and firmly attach the chip. In chip and wire multi-chip technology, each chip is die attached to an interconnect substrate and wire bonded to the substrate.
Due to the absence of external leads in chips intended for flip-chip technology or chip and wire technology (hereinafter both flip-chip and chip and wire technologies will be designated "bare chip"), the standard test and burn-in sockets cannot be used. The bare chips are not compatible with the test sockets used with standard packaged chips due to no external leads. Therefore, bare chips typically are not AC and burn-in tested prior to installation on a circuit board, which frequently results in nonfunctional boards due to bad bare chips. Thus, a need has arisen for a method and apparatus to allow bare chips to be adapted to a socket-type tester to allow AC and burn-in testing.